In this paper I propose a novel interpretation of Kant’s proof of the existence of the outer world in the Refutation of Idealism. According to this interpretation, Kant’s proof does not provide a regressive explanation of our capacity to determine the temporal order of our experiences. Rather, it expresses a counterfactual reflection on what it takes for something to be actual in contrast to being merely imagined. On the ground of this reflection, Kant argues against the Cartesian sceptic that, even (...) if all our representations of empirical objects other than ourselves failed to be veridical, we would still know a priori that in every situation in which we, as thinking things, actually exist, something outside us in space must necessarily exist. (shrink)